AKR/N and BALB/c Cum mice differ greatly with respect to their capacity to develop immunological memory to lipopolysaccharide (LPS) derived from Escherichia coli 0113 (LPS 0113). Substantial memory can be induced in BALB/c Cum mice primed with extremely low doses (10 to the -5 Mug) LPS 0113; however, only a modest degree - at best - of memory is induced in AKR/N mice, regardless of the dose of LPS 0113 used for priming. Since the generation of memory to LPS 0113 in BALB/c Cum mice proceeds in a cyclic manner, memory may play an important role in the expression of a cyclic antibody response to this antigen. Other studies on the antibody response to Type III pneumococcal polysaccharide have shown that the expression of suppressor T cell activity is cyclic with a periodicity of about 3 days; the kinetic pattern obtained is associated with concurrent stages of Velban sensitivity that likewise are cyclic. This implies that suppressor T cells proliferate in an ordered manner in response to a "specific signal" generated after exposure to antigen.